title: Direct evidence in men for a role of endogenous oestrogens on gonadotrophin release.
abstract: In six healthy subjects serum oestradiol was selectively decreased by administering an aromatase activity inhibitor, hydrotestolactone (HT). After HT administration serum oestradiol (Oe2) decreased from 18.7 +/- 2.3 (SEM) to 6.7 +/- 0.6 pg/ml whereas testosterone (T) and dihydrotestosterone (DHT) blood levels were not modified. These oestradiol changes were associated with a significant increase in serum LH and FSH concentrations (P less than 0.001). The administration of tamoxifen, an oestrogen antagonist, to 5 subjects caused a sharp increase in LH and FSH levels (P less than 0.001). Oe2 was unchanged after the treatment with tamoxifen, whereas T levels were significantly higher. The sum of these data suggests that oestradiol under physiological conditions plays a specific role in the feedback mechanism of gonadotrophin release.
mesh_terms: D000293:Adolescent; D000328:Adult; D013196:Dihydrotestosterone / Q000097:blood; D004958:Estradiol / Q000097:blood*; D005640:Follicle Stimulating Hormone / Q000097:blood*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology; D013629:Tamoxifen / Q000494:pharmacology; D013738:Testolactone / Q000031:analogs & derivatives* / Q000494:pharmacology; D013739:Testosterone / Q000097:blood
chemical_list: D010906:Pituitary Hormone-Releasing Hormones; D013196:Dihydrotestosterone; D013629:Tamoxifen; C018155:testololactone; D013739:Testosterone; D004958:Estradiol; D013738:Testolactone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone